In recent years, high speed electronic printing has improved both in quality and in the speed with which the printing is accomplished. However, those skilled in this particular art are continuously searching for ways to further increase the speed of the printers. The faster the printer can operate, the more marketable it is.
Higher speeds must not adversely effect the resolution, contrast and overall quality of the printed material. Presently available printers often use scanners comprising a rotating polygon disk with partially illuminated facets to direct light at a drum having a photo sensitive layer for transferring data to be printed. While single beam scanners are used for slow speed printing, for high speed printing, a multiple beam light source is generally used. However, the duty cycle of the polygon facets in the presently available scanners operating in an under scanned mode is about 50% as a result of a minimum beam size constraint imposed by optical resolution requirements and limitations on the polygon diameter due to its high rotational speed.
In the past those skilled in the art have attempted to increase the speed of the scanner, thereby increasing the speed at which the printers operate by increasing either the rotational speed of the polygon disk, by increasing the number of polygon facets, or by increasing the number of light beams from the source. It has been found that the possibility of increasing each of these parameters is technologically limited or highly expensive. For example, increasing the speed of rotation of the scanners has been frustrated by inertial facet deformation and air friction forces. The same frustration was met in attempting to increase the number of polygon facets. As the number of light beam sources is increased, optical aberrations caused by off-axis light sources cause innumerable problems. Thus, in the art as known, attempts at increasing the speed of the scanning process may have reached a limit.